This application claims the priority of 100 62349.2 filed Dec. 14, 2000 and PCT/EP01/13655, filed Nov. 23, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method and to an arrangement for controlling and/or regulating a load of a vehicle, for example of a passenger car or utility vehicle.
Such methods and arrangements are generally known. By way of example, reference is made in this regard to German Reference DE 44 07 475 A1. Here, both the load and the fuel/air ratio are influenced on the basis of a setpoint value for the torque which is to be output by the drive unit. In particular, a fine, very precise adjustment of the engine torque is provided, which improves the traveling comfort. In addition to such requirements which improve the traveling comfort or the emission of exhaust gases, further factors such as safety, environmental protection and the saving of energy are significant nowadays. This includes also protecting the population against noise pollution. As the volume of traffic increases and population density becomes higher, the requirements in terms of reducing damaging environmental effects due to traffic noise are becoming more stringent. In order to protect the population against traffic noise and to ensure compliance with immission limiting values in accordance with the traffic noise protection ordinance 16. BImSchV, public roads are usually diverted around populated areas or appropriate velocity limits are imposed on roads, or driving bans are even declared.
JP 04238749 A describes a method for minimizing the noise level of an engine, which method uses the current velocity of the vehicle and the current position of the gas pedal to control the rotational speed transmission ratio and the throttle valve position of the engine.
The object of the invention is therefore to specify a method and an arrangement for controlling and/or regulating a load of a vehicle in which the noise emission or noise emission caused by the vehicle is improved.
The present invention involves a method for controlling and/or regulating a load of a vehicle which acts as an accelerating or decelerating torque, the instantaneous loading of the vehicle being determined by means of at least one operating variable of the vehicle by means of a pickup unit, and the operating variable being controlled and/or regulated by means of a control unit or regulator unit as a function of a noise level resulting from the instantaneous loading of the vehicle. By taking into account in this way the operating and/or ambient noises of the traveling vehicle, caused in particular by the load of the vehicle itself and the process of regulating it, the noise emissions and imissions which are caused by the traveling process can be considerably reduced. Moreover, the control/regulation of the load which correlates to the noise level permits the traveling comfort to be increased. In addition, depending on the degree to which noise is reduced or the radiation of noise is limited by means of the method, it also becomes possible to travel on roads and in downtown areas and regions in which driving has been banned for noise reasons.
The noise-related operating variable regulation and/or control which reduces the load-related and vehicle-related noise emission/imission is adapted to the functions for setting the vehicle drive. It is essential here that a setpoint torque for controlling/regulating the vehicle as a function of the noise level and information on the dynamics with which this torque request is to be set are predefined by means of the control unit or regulator unit (also referred to as torque interface, referred to below as control unit) by reference to the instantaneous loading. Here, which subsystems (control or regulation systems, for example rotational speed regulator) are involved in the torque interface and the way in which they are coordinated with one another are completely irrelevant. The preferred use of noise-related characteristic curve diagrams for various regulating and/or control variables which represent the operating variable and in which the requirements are predefined with different dynamics and with different objectives makes it possible to allow for the different subsystems.
The invention is also based on the idea that, in order to comply with noise limiting values, for example in residential areas or in the vicinity of hospitals, the vehicle should be limited in terms of its noise emission. The operating variable on which the noise level is based is expediently used as the operating variable which is to be controlled or regulated. As a result, both the ambient noises and the operating noises of the vehicle which are caused by the instantaneously output power are taken into account in the control or regulation of the power. The factors which are relevant for the generation of the noise in terms of the operating variable to be regulated or controlled are taken into account by this regulating and/or controlling process and appropriately influenced. For example, the selection of the transmission ratio of a shiftable or infinitely variable transmission is a noise-related factor.
A rotational speed, a torque, a velocity and/or an acceleration are advantageously used as the operating variable. Here, the change in the rotational speed is used to change the torque profile with the objective of achieving a higher engine power at a low rotational speed, as a result of which the noise emission is kept particularly low. In other words, when the vehicle is at full load and at a low rotational speed, less noise is generated by the vehicle. Alternatively, or in addition, a transmission speed and/or a transmission ratio in an infinitely variable force transmission arrangement are used as operating variable. Advantageously, the acceleration is monitored and used as the most important operating variable influencing the generation of noise. The variable which is to be controlled/regulated and which is to bring about the desired acceleration of the vehicle is the instantaneously called load of the engine. If the calling of the load which is to be brought about by the desired acceleration would result in a generation of noise which lies above a specific limiting value, the control unit reduces the load which is actually called to the extent that the limiting value is not exceeded.
In a preferred embodiment, in order to determine the respective setpoint value of the operating variable, various characteristic diagrams in which the dependence of the noise level on the instantaneous velocity, rotational speed, load and/or the selected gear velocity is mapped are stored. A desired acceleration can be achieved, for example in a low gear velocity given a low load and a high rotational speed, and at the same time give rise to a different noise level (higher or lower) than another characteristic diagram point which implements the same acceleration by means of a high load with a lower rotational speed in the higher gear velocity. The setpoint torque which is processed with other setpoint torques, for example from the transmission controller, from a vehicle movement dynamics regulator or other subsystems of the drive control (for example from a digital map) is determined by reference to the characteristic curve diagrams.
The noise level is advantageously determined by reference to the instantaneous loading of the vehicle and/or by reference to ambient noises. For this purpose, various measuring curves are sensed for the noise level as a function of the type of vehicle, age of vehicle, type of engine of the vehicle, velocity of the vehicle, design of the vehicle, acceleration of the vehicle on different road coverings and/or tire parameters and/or meteorological events (for example wind, rain) and are stored in the form of characteristic curve diagrams by reference to which the noise level representing the instantaneous loading of the vehicle is then determined. Alternatively, or in addition, ambient noises and/or operating noises are sensed and processed by means of the pickup unit, for example by means of a microphone. As a result, the sound emission resulting from the interaction between tire and underlying surface or body of the vehicle and wind can be detected and can thus be taken into account in the noise-reducing control/regulation of the load. The pickup unit can be embodied here as a fixed and/or mobile noise-sensing unit. Moreover, such fixed and/or mobile noise-sensing units can be used to take into account ambient noises which cannot be influenced during the control/regulating process (for example the maximum value can be corrected upward in the case of rain).
The noise level is expediently monitored for compliance with a limiting value or with a guide value. For example, the maximum permissible noise level for various regions, for example residential area, commercial area, is different. The compliance with these predefined limiting values for the maximum permissible noise level is taken into account in a supplementary way in the control/regulation of the operating variable. The locality-related limiting values are stored, for example, in the form of a table in a database.
In order to permit the noise of the traveling vehicle to be reduced in a locality-related fashion, the operating variable is preferably controlled and/or regulated as a function of the instantaneous position of the vehicle. Here, corresponding limiting values are taken into account for the noise level for various geographic coordinates in the control/regulation of the operating variable. As a result, for example, greater reduction of noise than the customary noise reduction level is made possible in zones where noise is critical. For this purpose, the pickup unit preferably comprises a location determining system and/or a geographic information system. Depending on the type and design of the pickup unit, the location determining system and/or the geographic information system may be integrated or be connected to the pickup unit in a decentralized fashion via an interface.
Alternatively, or in addition, the operating variable is advantageously controlled and/or regulated as a function of time. As a result, a necessary reduction in noise which is adapted to times of day and night is made possible and resulting setpoint values can be predefined for the respective operating variable. Alternatively, or in addition, the operating variable can be predefined manually, for example by the driver of the vehicle or another occupant of the vehicle.
The present invention also involves an arrangement for controlling and/or regulating a load of a vehicle with a pickup unit for determining the instantaneously called load of the vehicle by reference to at least one operating variable of the vehicle, and a control unit for controlling and/or regulating the operating variable as a function of a noise level resulting from the instantaneous loading of the vehicle.
In order to take into account external noises which cannot be influenced and/or are related to the vehicle, the pickup unit expediently comprises a noise sensing system for determining the ambient noises. For example, fixed and/or mobile noise sensing systems, for example sound sensors, microphones, are used for this. For example, airborne or solid-borne sensors are used for determining the airborne or solid-borne sound. The pickup unit is advantageously provided for sensing a velocity, an acceleration (deceleration) and/or a drive torque in order to determine the instantaneous load on the vehicle. As a result, the noise level which results from the instantaneous loading can be determined by reference to characteristic curve diagrams stored in a data memory, for example.
Alternatively, and/or in addition, a location-determining system is preferably provided for determining the instantaneous position of the vehicle and/or an information system is provided for determining a locality-related noise level which results therefrom. This makes it possible to comply with a maximum permissible noise level at a locality by setting the operating variable by means of a corresponding setpoint value.
Alternatively, and/or in addition, the control unit comprises an input device for manually controlling and/or regulating the operating variable. As a result, it is possible to switch off the noise-related regulation/control of the load in a situation which is critical for traveling safety, for example. It is possible, for example in a critical traffic situation, to avoid an accident as a result of a load which exceeds the noise limiting value being called. The control/regulation of the load can be influenced, if necessary switched off entirely, either manually by an operator, for example the driver, or automatically by means of a superordinate regulating/controlling process.
Furthermore, predefined values of external systems, in particular of a traffic control system, are expediently taken into account in the control and/or regulation of the operating variable by means of the control unit or regulator unit via the pickup unit. The predefined values of external systems relating to the control and/or regulation of the operating variable are preferably approved by the driver of the vehicle and/or by an occupant of the vehicle by means of the control unit or regulator unit. The driving behavior can thus be adapted at any time to the given travel situation.
An output unit, for example a display, is preferably provided for outputting vehicle-related and/or ambient data such as, for example, the instantaneous position of the vehicle, locality-related and time-related noise limiting values, noise guide values and noise threshold values, vehicle-related operating variables and regulating or control states of the control unit or regulator unit. The interventions of the control unit or regulator unit into the vehicle system during the control and/or regulation of the operating variable and vehicle-related operating variables, for example velocity, acceleration, rotational speed, torque, are preferably stored in a data memory for documentation purposes. Statistics, for example noise statistics, can be created from the data stored in the data memory. Alternatively, or in addition, recommendations for maintenance and repair of the vehicle, for example time when the exhaust gas system should be exchanged, can be derived from the data stored in the data memory.
The interventions of the control unit or regulator unit into the vehicle system during the control and/or regulation of the operating variable can advantageously be transferred to an external system, for example traffic control system, for monitoring purposes. The control unit can preferably be activated or deactivated by external systems, for example traffic control systems or toll points, by means of the pickup unit. This makes it possible for the control unit to optimize the traffic flow. Moreover, alternatively, or in addition, further variables, for example consumption, emissions of noxious substances, wear and traveling comfort, are taken into account in the interventions by the control unit in the vehicle system in order to control and/or regulate the operating variables. Depending on the type and design as well as complexity of the control functions and/or regulating functions of the control unit, artificial intelligence methods, for example neural networks and/or fuzzy logic, are used.
The advantages which are achieved with the invention comprise in particular the fact that, in order to reduce the noise pollution by the vehicle in a perceptible and enduring fashion, the influencing variable or operating variable which is relevant to the generation of noise are controlled and/or regulated as a function of the instantaneous noise level. The noise limitation resulting from such power limitation permits local noise limiting values or noise guide values, for example in the region of downtown areas and hospitals, to be complied with. It makes it possible, for example, to limit the rotational speed of a vehicle traveling at full load in such a way that the vehicle does not exceed a respective noise level.